Treatment of Young Adults with Comorbid AUD/MDD: A Pilot Medication Trial This proposal is written in response to PA-13-161 entitled, Alcohol Use Disorders: Treatment, Services, and Recovery Research (R21). Recent reports have shown that alcohol misuse is a particularly serious problem among the 18 to 25 year old age group. Previous medication trials with SSRI antidepressants among young adults with co-occurring depressive disorders, including our own recent trials with SSRI medications, have produced disappointing results, especially for decreasing the level of alcohol consumption. Mirtazapine is a non-SSRI medication with a unique structure and mechanism of action. Recent study results suggest that mirtazapine is more effective than other antidepressants for treating non-comorbid depression. A few recent studies with mirtazapine have been conducted among subjects with comorbid AUD/MDD, and those studies have demonstrated efficacy for mirtazapine for decreasing the depressive symptoms and the alcohol craving of subjects with comorbid AUD/MDD. However, those studies did not measure level of alcohol consumption, so it is unclear whether mirtazapine decreases the level of alcohol use of that comorbid population. The results of our own very recent open label pilot study suggest robust within-group efficacy for mirtazapine for decreasing both the level of alcohol use and the depressive symptoms of comorbid subjects. However, that pilot study did not include a placebo control group, so the efficacy of mirtazapine versus placebo for decreasing the level of alcohol use among persons with comorbid AUD/MDD remains unclear. This grant submission proposes to conduct a first double-blind, placebo-controlled pilot study to provide a preliminary assessment of the efficacy of mirtazapine versus placebo for decreasing both the alcohol use and depressive symptoms of young adults with comorbid AUD/MDD. If results (effect sizes) from the proposed study are found to be promising concerning outcome differences between the mirtazapine and placebo groups, then we will use those findings to apply for an R01 study to definitively assess the efficacy of mirtazapine for treating young adults with AUD/MDD.